A reference voltage generating apparatus to restrain power consumption is known as a conventional technology. This reference voltage generating apparatus includes an operational amplifier. The reference voltage generating apparatus includes an intermittent operation means to cause this operational amplifier to operate only for a predetermined period of time when the reference voltage generating apparatus normally operates. A switchover of the operation is controlled by a digital signal. The digital signal is switched ON/OFF by an oscillator. When the digital signal is switched ON, a capacitor is charged with electric charges. When the digital signal is switched OFF, the operational amplifier for supplying a reference voltage stops, and instead the capacitor continues to supply the reference voltage.
However, in the conventional technology described above, the voltage retained by the capacitor is settled eventually to a ground potential by a parasitic resistance of the capacitor. Hence, there is a necessity for charging the capacitor with the reference voltage at every interval of a fixed period of time, and an intermittent period (OFF-period) cannot be extended, thereby disabling the power consumption from decreasing.